Flexible compositions based on propylene polymers

ABSTRACT

The flexible compositions having no elastomeric fractions comprise: 
     A) from 10 to 90 parts by weight of random copolymer of propylene and at least one comonomer selected from ethylene and C 4 -C 8  alpha-olefins having a melting point of at least 100° C. and not exceeding 140° C. and a flow index measured at 230° C. under a weight of 2.16 kg (ASTM standard D1238, 1986) of from 0.5 to 15 g/10 min, and 
     B) from 90 to 10 parts by weight of plastomer prepared with participation of a metallocene catalyst and consisting of a random copolymer of ethylene and at least one C 3 -C 10  alpha-olefin having a density of from 0.860 to 0.920 g/cm 3 , a melt flow index measured at 190° C. under a weight of 2.16 kg (ASTM standard D1238, 1986) of from 0.5 to 30 g/10 min, and a molecular mass distribution M w /M n  of at most 4. 
     These compositions provide an excellent compromise between flexibility and low-temperature impact resistance and heat resistance. They are suitable for producing flexible mouldings and very particularly for the manufacture by extrusion of films, of flexible sheeting, and of cables.

The present invention relates to flexible compositions based onpropylene polymers. More particularly, it concerns flexible compositionsbased on random copolymers of propylene and on plastomers having noelastomeric fractions.

Flexible polymeric compositions and polymers have many outlets insectors as varied as films, sheeting, the covering of soils, cables,etc. Plasticized vinyl chloride polymers are often used for theseapplications. However, these can cause problems connected to migrationof the plasticizers used to provide their flexibility, or else connectedto the emission of chlorinated products when they are incinerated.

An alternative previously proposed is recourse to what are known asflexible propylene polymers, such as block copolymers of propylenecontaining semi-crystalline and/or crystalline fractions and elastomericfractions (cf. for example EP-A-373660 and EP-A-416379). Anotherprevious proposal is to prepare flexible compositions by mixing blockcopolymers of propylene containing elastomeric fractions with plastomersconsisting of copolymers of ethylene with alpha-olefins prepared withparticipation of metallocene catalysts (WO 98/54260).

It is an object of the present invention to provide novel flexiblecompositions based on propylene polymers having no elastomericfractions. The invention therefore relates to flexible compositionsbased on propylene polymers having no elastomeric fractions comprising:

A) from 10 to 90 parts by weight of random copolymer of propylene and atleast one comonomer selected from ethylene and C₄-C₈ alpha-olefinshaving a melting point of at least 100° C. and not exceeding 140° C. anda flow index measured at 230° C. under a weight of 2.16 kg (ASTMstandard D1238, 1986) of from 0.5 to 15 g/10 min, and

B) from 90 to 10 parts by weight of plastomer prepared withparticipation of a metallocene catalyst and consisting of a randomcopolymer of ethylene and at least one C₃-C₁₀ alpha-olefin having adensity of from 0.860 to 0.920 g/cm³, a melt flow index measured at 190°C. under a weight of 2.16 kg (ASTM standard D1238, 1986) of from 0.5 to30 g/10 min, and a molecular mass distribution M_(w)/M_(n) of at most 4.

The overall content of monomeric units derived from ethylene and/or fromC₄-C₈ alpha-olefins in the random propylene polymer A) is generallybetween 3 and 20% by weight. The comonomer(s) entering with propyleneinto the composition of the random copolymer A) is/are generallyselected from ethylene and C₄-C₆ alpha-olefins. Preference is given toethylene, butene and hexene and in particular to ethylene and butene.

For the purposes of the present invention, the content of monomericunits derived from ethylene and/or from C₄-C₈ alpha-olefins in therandom copolymer A) is determined by FOURIER-transform IR spectrometry.In particular, the content of monomeric units derived from ethylene isdetermined using the absorption bands at 732 cm⁻¹ and 720 cm⁻¹, and thecontent of butene is determined using the band at 767 cm⁻¹.

The random copolymers of propylene A) used in the compositions accordingto the invention advantageously have a melting point of at least 105°C., mostly not exceeding 135° C.

One first family of random copolymers of propylene A) which are wellsuited to preparation of the flexible compositions according to theinvention consists of copolymers of propylene and ethylene containingfrom 3 to 10% by weight, preferably from 3 to 6% by weight, and moreparticularly from 3.5 to 5.5% by weight, of monomeric units derived fromethylene. This family of random propylene copolymers provides flexiblecompositions having excellent heat resistance (retention of flexibilityat high temperature).

Among this first family of random copolymers preference is given tocopolymers whose melting point (Tf) complies with the followingrelationship

Tf≦157.6° C.−x5° C.  (1)

where x is the percentage by weight of ethylene, based on copolymer A)

A second family of random propylene copolymers A) which is well suitedto preparation of the flexible compositions according to the inventionconsists of the copolymers of propylene and butene containing from 14 to20% by weight of monomeric units derived from butene. This family ofrandom propylene copolymers provides compositions with higherflexibility than the ethylene copolymers mentioned above, but their heatresistance is slightly lower.

Among this second family of random copolymers of propylene A) goodresults are given by the copolymers whose melting point (Tf) complieswith the relationship (2) below:

Tf<158° C.−y1.78° C.  (2)

in which y is the percentage by weight of butene, based on the copolymerA).

A third family of random copolymers of propylene A) which are wellsuited to preparation of the flexible compositions according to theinvention consists of terpolymers of propylene, ethylene and butenecontaining from 0.5 to 2.5% by weight of monomeric units derived fromethylene and from 5 to 19.5%, preferably from 5 to 15%, by weight ofmonomeric units derived from butene.

In the case of this third family, use is most often made of polymerscomplying with the relationship (3)

Tf<159.3° C.−x7.87° C.−y1.98° C.−0.43 xy° C.  (3)

in which x and y are respectively the % figures by weight for ethyleneand butene.

The random propylene copolymers A) which are very particularly preferredfor the purposes of the present invention are random copolymers ofpropylene and ethylene.

The random copolymers of propylene A) generally have a flexural modulus(EMod) measured at 23° C. in accordance with the ASTM standard D790M offrom about 400 to 800 MPa. They advantageously have a flow indexmeasured at 230° C. under a weight of 2.16 kg (ASTM standard D1238,1986) not exceeding 10 g/10 min. Preference is also given to randomcopolymers of propylene A) which have uniform distribution of themonomeric units derived from the (isotactic) comonomer(s).

The random copolymers of propylene A) entering into the flexiblecompositions according to the invention may be prepared by any knownprocess for the copolymerization of propylene with ethylene and/oralpha-olefins, for example by a process in the gas phase, or else indispersion in the liquid phase in liquid monomer, and making use of anyknown Ziegler-Natta catalytic system of sufficient activity andproductivity capable of polymerizing propylene stereospecifically andallowing the required amounts of ethylene and/or alpha-olefin to beincorporated into the polymer.

Preferred random copolymers (A) are advantageously obtained bycopolymerization of propylene and ethylene and using catalytic systemscomprising a solid based on titanium trichloride, an alkylaluminiumcompound, and optionally an electron donor. These catalytic systems havein particular been described in the patent applications EP-A-0261727 andEP-A-0334411, and in the patents U.S. Pat. Nos. 5,204,305 and 4,210,729(SOLVAY POLYOLEFINS EUROPE-BELGIUM). For a given overall content ofethylene, the random copolymers of propylene and ethylene prepared withparticipation of these catalytic systems, when compared with copolymersprepared with participation of what are known as supported catalysts,have a more random character, reduced oligomer content, and betterpowder morphology.

Very particularly preferred random copolymers of propylene and ethylenecomply with the equation:

[C _(2×5)+]≦0.0094[C _(2×3)]²−0.0054[C _(2×3)]+0.0375

in which [C_(2×5)+] and [C_(2×3)], expressed in g/kg and evaluated byinfrared absorption spectrometry are respectively:

[C_(2×5)+]: the content of ethylenic units corresponding to theinsertion of two, or more than two, ethylenic units between twopropylenic units, measured at 720 cm⁻¹, and

[C_(2×3)]: the content of ethylenic units corresponding to the insertionof one ethylenic unit between two propylenic units, measured at theabsorption maximum at about 732 cm⁻¹.

The overall content of monomeric units derived from the C₃-C₁₀alpha-olefins in the plastomer B) is generally between 2.5 and 13 mol %.

The comonomer(s) entering with ethylene into the composition of theplastomer B) prepared with participation of a metallocene catalystis/are generally selected from C₃-C₈ alpha-olefins. They areadvantageously selected from alpha-olefins such as propylene, butene,hexene and octene, preferably from butene and octene. A veryparticularly preferred comonomer is octene. The plastomer B) generallyhas a single melting peak in the area of from 50 to 110° C., preferablybetween 60 and 105° C.

The plastomer B) preferably has a density amounting to 0.865 to 0.905g/cm³. Its melt flow index measured at 190° C. under a weight of 2.16 kg(ASTM standard D1238) is preferably below 20 g/10 min, still moreparticularly below 10 g/10 min.

The plasomers B) which have to be prepared with participation of ametallocene catalyst have properties distinct from those of ethylenecopolymers having similar flow indices and densities but prepared withparticipation of multisite catalysts, such as Ziegler-Natta catalysts.In particular, they are characterized by a narrow molecular massdistribution and uniform distribution of the comonomers. The molecularmass distribution M_(w)/M_(n) is most often below 3.5, but is at least1.7. It is preferably between 3 and 1.8. The plastomers B) are also mostoften characterized by a comonomer distribution breadth index (CDBI), asdefined in the patent application WO 97/38424, above 60. This index ispreferably above 80 and still more particularly above 90.

For a given content of comonomers the plastomers prepared withparticipation of metallocenes, when compared with plastomers preparedwith participation of multisite catalysts, such as Ziegler-Nattacatalysts, have a more random character, reduced oligomer content, andbetter powder morphology (free-flowing powder).

The plastomers B) used in the flexible compositions according to theinvention constitute known products which are commercially available. Byway of examples of plastomers B) particularly well suited for producingthe flexible compositions according to the invention, mention may bemade of the plastomers marketed by EXXON with the trademark “EXACT”.These are free-flowing granules.

The flexible compositions according to the invention advantageouslycomprise from 80 to 20 parts by weight of random propylene copolymer A)and from 20 to 80 parts by weight of plastomer B) and still moreparticularly from 70 to 30 parts by weight of random copolymer A) andfrom 30 to 70 parts by weight of plastomer B). It is self-evident thatthe compositions according to the invention may comprise one or morepropylene copolymers A) and/or one or more plastomers B). Thecompositions according to the invention may also comprise a propylenepolymer other than the copolymer A). Particular examples of thispropylene polymer are homopolymers of propylene and random propylenecopolymers containing up to 6% by weight of ethylene, other than thecopolymer A). The propylene polymer preferably has a melting point abovethat of the copolymer A).

The propylene copolymer A) and the propylene polymer are most often usedin ratios by weight of from 10:90 to 90:10, more particularly from 20:80to 80:20. Compositions according to the invention comprising aterpolymer of propylene such as that described above under copolymer A),the plastomer B) and a random copolymer of propylene and ethylenecontaining from 2 to 5% by weight of ethylene are particularly preferredsince they have a wider melting range while maintaining excellentflexibility and good heat resistance.

Other compositions according to the invention which have highsuitability are those which comprise a random propylene copolymercontaining from 3 to 6% by weight of monomeric units derived fromethylene and complying with the equation

[C _(2×5)+]≦0.0094[C _(2×3)]²−0.0054[C _(2×3)]+0.0375

[copolymer A)], plastomer B) and from 4 to 60 parts by weight of arandom copolymer of propylene and ethylene containing from 2 to 5% byweight of ethylene, other than the copolymer A).

The properties of flexible compositions according to the invention, andparticularly their flexibility and their heat resistance, are modifiableby varying the relative content of the polymeric constituents A) and B)and the nature of each of these. The flexible compositions according tothe invention generally have a flexural modulus (EMod) measured at 23°C. according to the ASTM standard D790M of at most 550 MPa, mostly atmost 500 MPa, but generally at least 50 MPa.

The flexible compositions according to the invention provide anexcellent compromise between flexibility, low-temperature impact strainand heat resistance over a wide application range (retention of lowmoduli at high temperature). In particular, they combine flexibility andlow-temperature impact resistance clearly improved over randomcopolymers of propylene A) and heat resistance (retention of lowflexible moduli at temperatures above 80° C.) clearly improved over theplastomers B). They are also transparent and have reduced oligomer(C₁₂-C₅₄) content, generally not exceeding 1250 ppm and mostly 1000 ppm.

The manner in which the compositions according to the invention areobtained is not critical. They may therefore be manufactured by any ofthe traditional processes known for mixing polymers in the melt. Themixture of random propylene copolymer A) and plastomer B) in the melt ismostly produced under conditions of temperature and residence time suchthat at least partial melting of the random propylene copolymer A) isinduced. They are preferably such that there is complete melting of therandom propylene copolymer. The mixing is generally carried out at atemperature not exceeding 35° C.; this temperature mostly does notexceed 300DC; it preferably does not exceed 250° C. The minimumtemperature at which the mixing in the melt is carried out is generallyequal to or above 100° C., mostly equal to or above 130° C.; it ispreferably equal to or above 140° C. Good results are obtained when thistemperature is equal to or above 200° C. but does not exceed 240° C.

The residence time for the action selected for the mixing process varieswith the nature of the polymeric constituents A) and B) and with themixing temperature. The ideal residence time may advantageously beevaluated from preliminary experiments.

A mixing of the random copolymer A) and the plastomer B) may be carriedout in any device known for this purpose. Use may therefore be made ofinternal or external mixers. Internal mixers are the most appropriate,and among these the most appropriate are continuous internal mixers,such as extruders. Extruders which can be suitable are particularlysingle-screw extruders, co-kneader extruders, co-rotating orcounter-rotating twin-screw extruders, intermeshing or non-intermeshing,and multiscrew extruders. It is preferable to use an extruder oftwin-screw type.

During the operation for mixing the random propylene copolymer A) andthe plastomer B), it is, of course, possible to incorporate into thecomposition the optional propylene polymer, and also various additives,non-limiting examples being stabilizers, acid scavengers, antioxidants,organic or mineral colorants, fillers, such as talc or glass fibres,etc. The random propylene copolymer(s) A), the plastomer(s) B) and theoptional propylene polymer are generally the only polymeric constituentsof the compositions according to the invention.

The compositions according to the invention may be used as a constituent(for example as masterbatch) for the ultimate preparation of othercompositions.

The flexible compositions according to the invention may be used in anyof the traditional processes for processing thermoplastic materials, forexample moulding, extrusion, or injection moulding, and in any apparatushabitually used for processing thermoplastic materials.

The flexible compositions based on propylene polymers according to theinvention are suitable for producing a wide variety of flexiblemouldings. They are particularly suitable for the manufacture of films,of flexible sheeting, or of cables (sheathing or insulation). They arealso suitable for the manufacture of soil coverings, piping andprofiles. The flexible compositions according to the invention areparticularly suitable for the manufacture, by extrusion, of flexiblesheeting or films, and also cables, and in particular of flexiblesheeting or films, and also of cables having a flexural modulus (EMod)measured at 23° C. in accordance with the ASTM standard D790M of at most450 MPa.

The examples below are intended to illustrate the invention.

EXAMPLES 1 TO 3C

Examples 1 and 2 illustrate the compositions according to the inventioncomprising a random propylene copolymer obtained as described in Example1 of the patent U.S. Pat. No. 5,204,305 (copolymer A) and a plastomerprepared with participation of a metallocene catalyst (plastomer B).Example 3C, given by way of comparison, relates to the copolymer A byitself.

In Example 1, a composition is prepared comprising 50 parts by weight ofcopolymer A and 50 parts by weight of plastomer B. In Example 2, acomposition is prepared comprising 70 parts by weight of copolymer A and30 parts by weight of plastomer B.

The random propylene copolymer A) used in Examples 1, 2 and 3 was acopolymer of propylene and ethylene containing 4.3% by weight ofethylene and having the following characteristics:

melting point: 133-132° C.

melt flow index (230° C., 2.16 kg—ASTM standard D1238, 1986): 4.50 g/qomin

[C_(2×3)]/[C_(2×5)+] ratio: 35/8

In Examples 1 and 2 use is made of the plastomer EXACT 8201, a copolymerof ethylene and octene having the following characteristics:

density: 0.882 g/cm³

melt flow index (at 190° C., 2.16 kg—ASTM standard D1238, 1986): 1 g/10min.

M_(w)/M_(n) ratio: about 2.4

The compositions according to Examples 1 to 3 comprise, in addition tothe polymeric constituent(s) detailed above, 2000 ppm of antioxidant and1000 ppm of acid scavenger. The compositions were prepared by mixingingredients and extrusion of the mixture in a Clextral BC45 twin-screwextruder, the temperature of the material being 209° C. The barrel ofthe extruder comprises 7 modules (six heating units and one conicalheating die with 6 small holes of size 4 mm). The screw units have adiameter of 55. mm, and the total length of the screw is 30D. Thetemperature profile of the extrusion screw was as follows:

Zone 1 : 81° C.

Zone 2 : 170° C.

Zone 3 : 179° C.

Zone 4 : 199° C.

Zone 5 : 199° C.

Zone 6 : 199° C.

Zone 7 : 198° C.

Zone 8 : 200° C.

Starting from extruded pellets, various properties of the compositionsaccording to Examples 1 and 2 and of the propylene copolymer accordingto Example 3C (comparative) were evaluated, and the results obtained arerecorded in Table 1, which also shows the standards utilized for theseevaluations. Thermal desorption is a measure of the content ofoligomers, obtained by gas-phase chromatography under helium at 275° C.The oligomers (C₁₂-C₅₄) extracted at 275° C. were trapped at lowtemperature (−196° C.) and then reheated to 350° C. and passed into thegas-chromatography column.

TABLE I Property Example No. evaluated Standard Unit 1 2 3C Melt flowASTM D1238 q/10 ˜3.5 ˜3.5 ˜4.5 index (230° C., min 2.16 kg) FlexuralASTM D790M MPa 275 400 700 modulus at 230° C. Impact ISO 180/1A ° C. nono fracture resistance at fracture fracture −40° C. (notched bar)Brittleness ASTM D746 ° C. <−60 −45 0 temperature Tensile ASTM D638M MPa19 24 21 strength Elongation at ASTM D638M % >600 >600 >600 breakMelting point ASTM D3418 ° C. 133 133 133 Vicat softening ASTM D1525 °C. 78 94 120 point Heat distortion ASTM D648 ° C. 36 38 ND* temperature(HDT) Shore D ASTM D2240 ° C. 47 51 62 hardness at 23° C. Thermal cf.above mg/kg 650 700 850 desorption (C₁₂-C₅₄ oligomers) *ND: notdetermined

EXAMPLES 4 to 6

Examples 4 to 6 illustrate compositions according to the invention inwhich the copolymer A) present is a terpolymer of propylene containing0.7% by weight of ethylene and 17.4% by weight of butene, and having thefollowing characteristics:

melting point: 120° C.

melt flow index:

The plastomer B) is the same as that of Examples 1 and 2 and thecompositions were obtained as described in the said examples. Theproperties of the compositions obtained in this way are given in TableII.

TABLE II Example No. Property evaluated Unit 1 2 3 Content of % 70 50 40copolymer A) Content of % 30 50 60 plastomer B) Melt flow index g/10 min3.2 2.8 2.5 (230° C., 2.16 kg) Flexural modulus at MPa 265 156 92 23° C.Impact resistance — no no no at −40° C. fracture fracture fracture(notched bar) Brittleness ° C. −55 <−60 <−60 temperature Tensilestrength MPa 11.1 7.9 6.5 Elongation at break % >600 >500 >500 Meltingpoint ° C. 80/110 76/114 74/109 Vicat softening ° C. 79 69.4 64.3 pointHeat distortion ° C. 34.5 30.2 not temperature (HDT) measurable Shore Dhardness at 50 46.2 41.9 23° C. Thermal desorption ppm 750 770 700(C₁₂-C₅₄ oligomers)

EXAMPLE 7

Example 7 illustrates a composition comprising 35 parts by weight of theterpolymer used in Examples 4 to 6, 30 parts by weight of EXACT 8201plastomer and 35 parts by weight of a random propylene copolymercontaining 3.2% by weight of ethylene and having a melt flow index of 2g/10 min. The composition, prepared as in the preceding examples, has:

melt flow index (230° C., 2.16 kg): 4 g/10 min

flexural modulus at 23° C.: 415 MPa

brittleness temperature: −41° C.

tensile strength: 20 MPa

elongation at break: >500%

melting point: 77/138/145° C.

Vicat softening point: 78.8° C.

heat distortion temperature (HDT): 37.7° C.

Shore D hardness at 23° C.: 51.7

thermal desorption (C₁₂-C₅₄ oligomers): 730 ppm

What is claimed is:
 1. A flexible composition based on one or morepropylene polymers having no elastomeric fractions, said flexiblecomposition comprising a blend of: A) from 10 to 90 parts by weight of arandom copolymer of propylene and at least one comonomer selected fromthe group consisting of ethylene and C₄-C₈ alpha-olefins, wherein saidrandom copolymer of propylene has a melting point of at least 100° C.and not exceeding 140° C. and a melt flow index measured at 230° C.under a weight of 2.16 kg (ASTM standard D 1238, 1986) of from 0.5 to 15g/10 min, and B) from 90 to 10 parts by weight of a plastomer preparedwith participation of a metallocene catalyst, wherein said plastomerconsists of a random copolymer of ethylene and at least one C₃-C₁₀alpha-olefin, and wherein said plastomer has a density of from 0.860 to0.920 g/cm³, a melt flow index measured at 190° C. under a weight of2.16 kg (ASTM standard D 1238, 1986) of from 0.5 to 30 g/10 min, and amolecular mass distribution M_(w)/M_(n) of at most 4, wherein saidrandom copolymer of propylene A is selected from the group consisting ofA1) copolymers of propylene and ethylene comprising from 3 to 6% byweight of monomeric units derived from ethylene; A2) copolymers ofpropylene and butene comprising from 15 to 20% by weight of monomericunits derived from butane; and A3) terpolymers of propylene, ethyleneand butene comprising from 0.5 to 2.5% by weight of monomeric unitsderived from ethylene and from 5 to 15% by weight of monomeric unitsderived from butene; and wherein said flexible composition has aflexural modulus (Emod) measured at 23° C. in accordance with ASTMstandard D790M of 500 MPa or less.
 2. The flexible composition based onone or more propylene polymers according to claim 1, wherein the randompropylene copolymer is selected from the group consisting of copolymersof propylene and ethylene comprising from 3.5 to 5.5% by weight ofmonomeric units derived from ethylene.
 3. The flexible composition basedon one or more propylene polymers according to claim 1, wherein therandom propylene copolymer has a flexural modulus (Emod) measured at 23°C. in accordance with the ASTM standard D790M of from about 400 to 800MPa and a melt flow index measured at 230° C. under a weight of 2.16 kg(ASTM standard D1238, 1986) not exceeding 10 g/min.
 4. The flexiblecomposition based on one or more propylene polymers according to claim1, wherein the plastomer consists of a random copolymer of ethylene andalpha-olefin containing from 2.5 to 13 mol % of an alpha-olefin selectedfrom the group consisting of butene and octene.
 5. The flexiblecomposition based on one or more propylene polymers according to claim1, wherein the plastomer consists of a random copolymer of ethylene andoctene.
 6. The flexible composition based on one or more propylenepolymers according to claim 1, wherein the plastomer has a density offrom 0.865 to 0.905 g/cm³, a melt flow index measured at 190° C. under aweight of 2.16 kg (ASTM standard D1238, 1986) below 20 g/10 min and amolecular mass distribution M_(w)/M_(n) below 3.5 but not less than 1.7.7. The flexible composition based on one or more propylene polymersaccording to claim 1, wherein said composition comprises from 80 to 20parts of the random propylene copolymer and form 20 to 80 parts of theplastomer prepared with participation of a metallocene catalyst.
 8. Theflexible composition based on one or more propylene polymers accordingto claim 1, wherein the one or more propylene polymers has a flexuralmodulus (Emod) measured at 23° C. in accordance with the ASTM standardD790M of at most 450 MPa.
 9. The flexible composition based on one ormore propylene polymers according to claim 1, comprising one or morerandom copolymers of propylene A) and one or more plastomers B.
 10. Theflexible composition based on one or more propylene polymers accordingto claim 1, further comprising a propylene polymer other than thecopolymer A).
 11. The flexible composition based on one or morepropylene polymers according to claim 10, wherein the propylene polymerother than the copolymer A) has a melting point above 140° C.
 12. Aflexible sheeting or film comprising the composition according toclaim
 1. 13. A cable insulation or cable sheathing comprising thecomposition according to claim
 1. 14. A flexible composition based onone or more propylene polymers of claim 1 wherein said flexiblecomposition has an oligomer (C₁₂-C₅₄) content or less than about 1250ppm.
 15. The flexible composition of claim 14 having an oligomer contentof less than about 1000 ppm.
 16. A flexible sheeting or film comprisingthe composition according to claim
 14. 17. A cable insulation or cablesheathing comprising the composition according to claim 14.